From: Xue Fuqiao <xfq.free@gmail.com>
To: help-gnu-emacs@gnu.org
Subject: Re: About `funcall'
Date: Tue, 05 Mar 2013 06:59:37 +0800 [thread overview]
Message-ID: <51352759.80206@gmail.com> (raw)
> Xue Fuqiao <xfq.free@gmail.com> writes:
>
>> In `yank-pop', there is an sexp about `funcall':
>>
>> (funcall (or yank-undo-function 'delete-region) (point) (mark t))
>>
>> IIRC the first argument for `funcall' should be a function, so I'm
>> confused with this usage. Can somebody explain it to me? Thanks.
>
> `or' returns the first argument that is not nil, or nil when all the
> arguments are nil.
I see, thanks.
> (defmacro .or (&rest args)
> (if (null args)
> 'nil
> (let ((var (gensym)))
> `(let ((,var ,(first args)))
> (if ,var
> ,var
> (.or ,@(rest args)))))))
>
> (macroexpand '(.or a b))
> --> (let ((#1=#:G90861 a)) (if #1# #1# (\.or b)))--
What does "(first args)" mean here? Does it mean "(car args)"?
next reply other threads:[~2013-03-04 22:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-04 22:59 Xue Fuqiao [this message]
[not found] <mailman.21404.1362437985.855.help-gnu-emacs@gnu.org>
2013-03-04 23:23 ` About `funcall' Pascal J. Bourguignon
[not found] <mailman.21339.1362401601.855.help-gnu-emacs@gnu.org>
2013-03-04 19:12 ` Raffaele Ricciardi
2013-03-04 19:15 ` Pascal J. Bourguignon
-- strict thread matches above, loose matches on Subject: below --
2013-03-04 12:52 Xue Fuqiao
2013-03-04 12:57 ` Xue Fuqiao
[not found] ` <mailman.21340.1362401871.855.help-gnu-emacs@gnu.org>
2013-03-04 14:11 ` Michael Heerdegen
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